Electrode arrays and cochlear implants including the same

ABSTRACT

A cochlear including a housing, an antenna, a stimulation processor operably connected to the antenna, and an electrode array, operably connected to the stimulation processor, including a flexible body defining a longitudinal axis, a proximal region and a distal region, a plurality of electrically conductive contacts on the flexible body, and at least one stiffener within the flexible body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of, and claims priority to,International Application No. PCT/US2017/060030, filed Nov. 3, 2017,which claims priority to U.S. Prov. App. Ser. No. 62/419,349, filed Nov.8, 2016, both of which are incorporated herein by reference in theirentireties.

BACKGROUND 1. Field

The present disclosure relates generally to the implantable portion ofimplantable cochlear stimulation (or “ICS”) systems and, in particular,to electrode arrays.

2. Description of the Related Art

ICS systems are used to help the profoundly deaf perceive a sensation ofsound by directly exciting the intact auditory nerve with controlledimpulses of electrical current. Ambient sound pressure waves are pickedup by an externally worn microphone and converted to electrical signals.The electrical signals, in turn, are processed by a sound processor,converted to a pulse sequence having varying pulse widths, rates, and/oramplitudes, and transmitted to an implanted receiver circuit of the ICSsystem. The implanted receiver circuit is connected to an implantablelead with an electrode array that is inserted into the cochlea of theinner ear, and electrical stimulation current is applied to varyingelectrode combinations to create a perception of sound. The electrodearray may, alternatively, be directly inserted into the cochlear nervewithout residing in the cochlea. A representative ICS system isdisclosed in U.S. Pat. No. 5,824,022, which is entitled “CochlearStimulation System Employing Behind-The-Ear Sound processor With RemoteControl” and incorporated herein by reference in its entirety. Examplesof commercially available ICS sound processors include, but are notlimited to, the Advanced Bionics™ Harmony™ BTE sound processor, theAdvanced Bionics™ Naida™ BTE sound processor and the Advanced Bionics™Neptune™ body worn sound processor.

As alluded to above, some ICS systems include an implantable cochlearstimulator (or “cochlear implant”) having a lead with an electrodearray, a sound processor unit (e.g., a body worn processor orbehind-the-ear processor) that communicates with the cochlear implant,and a microphone that is part of, or is in communication with, the soundprocessor unit. The cochlear implant electrode array, which is formed bya molding process, includes a flexible body formed from a resilientmaterial such as liquid silicone rubber (“LSR”) and a plurality ofelectrically conductive contacts (e.g., sixteen platinum contacts)spaced along a surface of the flexible body. The contacts of the arrayare connected to platinum lead wires that extend through the flexiblebody. Once implanted, the contacts face the modiolus within the cochlea.

The present inventors have determined that conventional electrode arraysare susceptive to improvement. For example, conventional electrodearrays can buckle during the insertion process, which necessitatesrepositioning and can result in damage to any still functioning nerveendings in the cochlea that allow residual hearing to occur. Inparticular, when a thin electrode array (e.g., an electrode array with adiameter of about 0.33 mm in the apical-most region that graduallytapers up to about 0.6 mm to about 1.0 mm at the basal region) that isconfigured for placement against the lateral wall is inserted into anopening in the cochlea, such as an opening formed by the “round window”technique or a cochleostomy, the surface tension at the meniscus of thecochlea fluid may be sufficient to cause the distal tip the electrodearray to deflect as the tip enters the opening. Additionally, the baseportions of thin electrode arrays sometimes buckle mid-way through theinsertion procedure. One conventional method of stiffening an electrodearray so that it can resist buckling is to embed one or more rods orstrips of relatively stiff material into the array. The presentinventors have determined that, because such rods and strips tend to besharp and point in the longitudinal direction, they can tear through theelectrode array and/or damage the relatively fragile platinum wires.Moreover, such rods and strips can result in the mid-portion of theelectrode array being too stiff to properly curl around the modiolus.Exemplary methods of stiffening electrode arrays are disclosed in U.S.Pat. Nos. 8,249,724, 8,812,121, 8,880,193, 9,033,869, 9,037,267, and9,492,654 and U.S. Pat. Pub. No. 2011/0137393.

SUMMARY

A cochlear implant in accordance with one of the present inventions mayhave a housing, an antenna, a stimulation processor operably connectedto the antenna, and an electrode array, operably connected to thestimulation processor, including a flexible body defining a longitudinalaxis, a proximal region and a distal region, a plurality of electricallyconductive contacts on the flexible body, and at least one stiffenerloop within the flexible body.

A cochlear implant in accordance with one of the present inventions mayhave a housing, an antenna, a stimulation processor operably connectedto the antenna, and an electrode array, operably connected to thestimulation processor, including a flexible body defining a longitudinalaxis, a proximal region and a distal region, a plurality of electricallyconductive contacts on the flexible body, and at least one undulatingstiffener within the flexible body and electrically isolated from theelectrically conductive contacts.

A cochlear implant in accordance with one of the present inventions mayhave a housing, an antenna, a stimulation processor operably connectedto the antenna, and an electrode array, operably connected to thestimulation processor, including a flexible body defining a longitudinalaxis, a proximal region and a distal region, a plurality of electricallyconductive contacts on the flexible body, and at least one multi-strandstiffener within the flexible body and electrically isolated from theelectrically conductive contacts.

There are a number of advantages associated with cochlear implantshaving such electrode arrays. For example, the at least one stiffenerprevents buckling of the associated portion of the electrode arraywithout introducing a sharp edge into the array. The at least onestiffener loop defines a plane that controls bending of the array, asdoes the at least one undulating stiffener.

The above described and many other features of the present inventionswill become apparent as the inventions become better understood byreference to the following detailed description when considered inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed descriptions of the exemplary embodiments will be made withreference to the accompanying drawings.

FIG. 1 is a plan view of a cochlear implant in accordance with oneembodiment of a present invention.

FIG. 2 is a perspective view of a portion of the cochlear leadillustrated in FIG. 1.

FIG. 3 is a perspective view of a portion of the cochlear leadillustrated in FIG. 1.

FIG. 4 is a bottom view of a portion of the cochlear lead illustrated inFIG. 1

FIG. 5 is a section view taken along line 5-5 in FIG. 4.

FIG. 6 is a section view taken along line 6-6 in FIG. 4.

FIG. 7 is a section view showing an exemplary contact configuration.

FIG. 8 is a top view of a portion of the cochlear lead illustrated inFIG. 1.

FIG. 9 is a perspective view of a portion of the cochlear leadillustrated in FIG. 1.

FIG. 10 is a side view of a portion of the cochlear lead illustrated inFIG. 1.

FIG. 11 is a top view of a portion of the cochlear lead illustrated inFIG. 1.

FIG. 12 is a section view taken along line 12-12 in FIG. 4.

FIG. 13 is a top view of a portion of the cochlear lead illustrated inFIG. 1.

FIG. 14 is a perspective view of a portion of the cochlear leadillustrated in FIG. 1.

FIG. 15 is a side view of a portion of the cochlear lead illustrated inFIG. 1.

FIG. 16 is a top view of a portion of the cochlear lead illustrated inFIG. 1.

FIG. 17 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 18 is a perspective view of a portion of the cochlear leadillustrated in FIG. 17.

FIG. 19 is a side view of the portion of the cochlear lead illustratedin FIG. 18.

FIG. 20 is a top view of the portion of the cochlear lead illustrated inFIG. 18.

FIG. 21 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 22 is a side view of a portion of the cochlear lead illustrated inFIG. 21.

FIG. 23 is a bottom view of a portion of the cochlear lead illustratedin FIG. 21.

FIG. 24 is a section view taken along line 24-24 in FIG. 23.

FIG. 25 is a section view of a portion of a cochlear lead in accordancewith one embodiment of a present invention.

FIG. 26 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 27 is a perspective view of a portion of the cochlear leadillustrated in FIG. 26.

FIG. 28 is a section view taken along line 28-28 in FIG. 26.

FIG. 29 is a side view of a portion of the cochlear lead illustrated inFIG. 27.

FIG. 30 is a top view of a portion of the cochlear lead illustrated inFIG. 27.

FIG. 31 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 32 is a perspective view of the stiffener of the cochlear leadillustrated in FIG. 31.

FIG. 33 is a top view of a portion of the stiffener illustrated in FIG.32.

FIG. 34 is a top view of a portion of the stiffener illustrated in FIG.32.

FIG. 35 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 36 a perspective view of the stiffener of the cochlear leadillustrated in FIG. 35.

FIG. 37 is a perspective view of a portion of the stiffener illustratedin FIG. 36.

FIG. 38 is a perspective view of a stiffener in accordance with oneembodiment of a present invention.

FIG. 39 is a perspective view of a portion of the stiffener illustratedin FIG. 38.

FIG. 40 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 41 is a perspective view of a portion of the cochlear leadillustrated in FIG. 40.

FIG. 42 is a side view of the portion of the cochlear lead illustratedin FIG. 41.

FIG. 43 is a section view taken along line 43-43 in FIG. 41.

FIG. 44 is an end view of the portion of the cochlear lead illustratedin FIG. 41.

FIG. 45 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 46 is a perspective view of a portion of the cochlear leadillustrated in FIG. 45.

FIG. 47 is a side view of the portion of the cochlear lead illustratedin FIG. 46.

FIG. 48 is a section view taken along line 48-48 in FIG. 46.

FIG. 49 is an end view of the portion of the cochlear lead illustratedin FIG. 46.

FIG. 50 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 51 is a perspective view of the stiffener of the cochlear leadillustrated in FIG. 50.

FIG. 52 is a top view of the stiffener illustrated in FIG. 51.

FIG. 53 is a side view of the stiffener illustrated in FIG. 51.

FIG. 54 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 55 is a perspective view of the stiffener of the cochlear leadillustrated in FIG. 54.

FIG. 56 is a top view of the stiffener illustrated in FIG. 55.

FIG. 57 is a side view of the stiffener illustrated in FIG. 55.

FIG. 57A is a top view of a stiffener in accordance with one embodimentof a present invention.

FIG. 58 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 59 is a perspective view of a portion of the cochlear leadillustrated in FIG. 58.

FIG. 60 is a side view of the portion of the cochlear lead illustratedin FIG. 59.

FIG. 61 is a top view of the portion of the cochlear lead illustrated inFIG. 59.

FIG. 62 is a perspective view of a portion of the stiffener of thecochlear lead illustrated in FIG. 58.

FIG. 63 is a perspective view of a portion of a stiffener in accordancewith one embodiment of a present invention.

FIG. 64 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 65 is a perspective view the stiffener of the cochlear leadillustrated in FIG. 64.

FIG. 66 is a side view of a portion of the stiffener illustrated in FIG.65.

FIG. 66A is a section view taken along line 66A-66A in FIG. 66.

FIG. 67 is a perspective view of a portion of a cochlear lead inaccordance with one embodiment of a present invention.

FIG. 68 is a top view the stiffener of the cochlear lead illustrated inFIG. 67.

FIG. 69 is a top view of a portion of the stiffener illustrated in FIG.68.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The following is a detailed description of the best presently knownmodes of carrying out the inventions. This description is not to betaken in a limiting sense, but is made merely for the purpose ofillustrating the general principles of the inventions.

One example of a cochlear implant (or “implantable cochlear stimulator”)in accordance with at least some of the present inventions isillustrated in FIGS. 1-5. The cochlear implant 100 includes a flexiblehousing 102 formed from a silicone elastomer or other suitable material,a processor assembly 104, a cochlear lead 106 with an electrode array108, and an antenna 110 that may be used to receive data and power byway of an external antenna that is associated with, for example, a soundprocessor unit. A positioning magnet 111 (FIG. 1) is located within amagnet pocket 113. The magnet 111 is used to maintain the position of aheadpiece transmitter over the antenna 110. The cochlear implant may, insome instances, be configured is manner that facilitates magnet removaland replacement. Here, the housing 102 may be provided with a magnetaperture (not shown) that extends from the magnet pocket 113 to theexterior of the housing.

The electrode array 108 includes a flexible body 112 and a plurality ofelectrically conductive contacts 114 (e.g., the sixteen contacts 114illustrated in FIG. 4) spaced along the bottom surface 116 of theflexible body. Suitable materials for the flexible body 112 include, butare not limited to, LSR, high temperature vulcanization (“HTV”) siliconerubbers, room temperature vulcanization (“RTV”) silicone rubbers, andthermoplastic elastomers (“TPEs”), while suitable materials for thecontacts 114 include, but are not limited to, platinum,platinum-iridium, gold and palladium. The contacts 114 may be referredto in numbered order, 1^(st) through 16^(th), with the contact closestto the tip 118 being the 1^(st) contact and the contact closest to thebase 120 being the 16^(th) contact. The exemplary flexible body 112 alsoincludes a longitudinally extending top surface 122 that does notinclude conductive contacts. Once implanted, the conductive contacts 114on the curved surface 116 face the modiolus within the cochlea.

The exemplary flexible body 112 has a circular shape in a cross-sectionperpendicular to the longitudinal axis LA of the electrode array 108(FIGS. 2 and 5). In other implementations, a truncated circular shape,with a flat top surface, may be employed.

Turning to FIG. 2, in addition to the electrode array 108, the exemplarycochlear lead 106 includes a handle 126, with a rectangular portion 128and a tapered portion 130, which may be gripped by the surgeon duringthe implantation surgery. The handle 126 also provides tension relieffor the lead wires 134, which do not run straight through the handle. Atubular member 132, which may consist of tubes of different sizes,extends from the handle 126 to the housing 102. The contacts 114 areconnected to lead wires 134 (FIG. 5) that extend through the flexiblebody 112 and tubular member 132 to a connector (not shown) in thehousing 102. The lead wires 134 may be formed from, for example,platinum-iridium or other suitable materials.

Turning to FIG. 6, the contacts 114 in the illustrated implementationare formed by placing a tubular workpiece into a mold, positioning thelead wire 134 that will be connected to that contact within theworkpiece, and then applying heat and pressure to the workpiece to forma semi-circular contact that is connected to a lead wire. A small gapmay remain between portions of the contacts 114. The gaps augment themechanical interconnection between the flexible body 112 and thecontacts 114. Alternatively, as illustrated in FIG. 7, the compressionand distortion of the malleable workpiece may cause the opposingportions workpiece to come into contact with one another along a seam140 in the otherwise identical electrode array 108′. In either case, thecontact formation process is repeated until all of the contacts areformed in the mold. The mold is then covered and resilient material isinjected into the mold to form the flexible body 112.

The exemplary electrode array 108 and other electrode arrays 108 a-108 mdescribed below are also provided with various structures that stiffenthe proximal region of the electrode array and/or the distal region ofthe electrode array to prevent buckling. The structures also controlbending and prevent unwanted rotation of those regions of the electrodearray.

Referring first to FIGS. 6-11, the proximal region of the exemplaryelectrode array 108 includes a stiffener loop 142 that is embeddedwithin the flexible body 112. In the illustrated implementation, thestiffener loop 142 is located within the handle tapered portion 130 andthe portion of the flexible body 112 adjacent to be base 120. Theexemplary stiffener loop 142 is a closed loop that includes a pair oflongitudinally extending side members 144 as well as proximal and distalcurved end members 146 and 148 that are connected to the side members.The stiffener loop 142 is offset from, and is coextensive with, the fourcontacts 114 that are adjacent to the base 120, i.e., contacts thirteento sixteen in the illustrated sixteen contact embodiment. The stiffenerloop 142 also defines a loop plane LP that may be parallel to thecontact plane CP defined by the top ends (in the illustratedorientation) of the contacts 114. In addition to preventing buckling ator near the base 120, the stiffener loop 142 controls the direction thatthe flexible body 112 bends, thereby preventing unwanted rotation of theflexible body during insertion, by virtue of the orientation of the loopplane LP. Alternate loop plane orientations may be employed asnecessary.

It should also be noted that the stiffener loop 142 is electricallyisolated from the electrically conductive contacts 114, as are the otherstiffener loops and other types of stiffeners described below. Moreover,as used herein, a “stiffener” is not a lead wire (such as a lead wire134), or a plurality of lead wires, that electrically connects one ormore electrically conductive contacts to a source of electricalstimulation current.

The longitudinally extending side members 144 (and other side membersdiscussed below) are parallel to one another and to the longitudinalaxis LA. In other implementations, the distance between thelongitudinally extending side members may increase, or decrease, fromthe proximal curved end member to the distal curved end member.

Turning to FIGS. 12-16, the distal region of the exemplary electrodearray 108 includes a stiffener loop 150 that is embedded within theflexible body 112. The configuration of the stiffener loop 150 may bethe same as the stiffener loop 142 (as shown) or different than thestiffener loop 142. In the illustrated implementation, the stiffenerloop 150 is located adjacent to the tip 118. The exemplary stiffenerloop 150 includes a pair of longitudinally extending side members 152 aswell as proximal and distal curved end members 154 and 156 that areconnected to the side members. The stiffener loop 150 offset from, andis coextensive with, the four contacts 114 that are adjacent to the tip118, i.e., contacts one to four in the illustrated sixteen contactembodiment. The stiffener loop 150 also defines a loop plane LP that maybe parallel to the contact plane CP defined by the top ends of thecontacts 114. In addition to preventing buckling at or near the tip 118,the stiffener loop 150 controls the direction that the flexible body 112bends, thereby preventing unwanted rotation of the flexible body, byvirtue of the orientation of the loop plane LP. Alternate loop planeorientations may be employed as necessary.

It should also be noted here that the curved stiffener loop ends 148,154 and 154 lack sharp edges. As such, they are less likely than aconventional stiffener to tear through flexible body 112.

With respect to materials, suitable materials for the stiffener loops142 and 150 (as well as the stiffeners described below with reference toFIGS. 17-69) include, but are not limited to, drawn filled tubing suchas DFT® wire. Suitable drawn filled tubing examples include a coremetal, such as platinum, palladium, silver or gold, with an outermaterial, such as Nitinol or the nickel-cobalt alloy sold under thetradename MP35N®. Other suitable material examples are titanium,stainless steel, carbon nanotubes and silica glass.

The exemplary cochlear lead 106 may be modified in variety of ways. Tothat end, and referring to FIGS. 17-20, the exemplary cochlear lead 106a is substantially similar to cochlear lead 106 and similar elements arerepresented by similar reference numerals. Here, however, the proximalregion of the exemplary electrode array 108 a includes a pair ofstiffener loops 142 and 142 a that are embedded in the flexible body112. In the illustrated implementation, the stiffener loops 142 and 142a are located within the handle tapered portion 130 and the portion ofthe flexible body 112 adjacent to be base 120. The exemplary stiffenerloop 142 a includes a pair of longitudinally extending side members 144a, a proximal curved end member (not shown) and a distal curved endmember 148 a. The stiffener loop 142 a is either slightly offset from(as shown) or rests on, and is coextensive with, the four contacts 114that are adjacent to the base 120, i.e., the contacts thirteen tosixteen in the illustrated sixteen contact embodiment, and is locatedbetween the stiffener loop 142 and the contacts. The stiffener loop 142a is also slightly wider than the stiffener loop 142 in that thedistance between the side members 144 a is greater that the distancebetween the side members 144.

In other implementations, the wider stiffener loop 142 a may be employedin place of (i.e., without) the stiffener loop 142. The stiffener loop142 a may be formed from the same material as the stiffener loop 142,when used together, and/or from the same material as the stiffener loop150, and/or from a different material the stiffener loop 142 or thestiffener loop 150. The wider stiffener loop 142 a, with or without thestiffener loop 142, may also be incorporated into the cochlear leads 106b-106 d described below with reference to FIGS. 21-30.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 b, is illustrated in FIGS. 21-24. The exemplarycochlear lead 106 b is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the proximal region of the exemplary electrode array 108 bincludes a pair of side wings 158 that extend laterally from theflexible body 112 and the handle tapered portion 130. The side wings 158extend to the fourth contact 114 from the base 120, i.e., contactthirteen in the illustrated sixteen contact embodiment, although thelength of side wings may be increased or decreased as necessary. Theside wings 158 prevent buckling at or near the base 120 and also controlthe direction that the flexible body 112 bends, thereby preventingunwanted rotation of the flexible body.

The stiffness of the side wings 158 may be augmented through the use ofa stiffener loop 160 that is embedded in the exemplary electrode array108 b. The stiffener loop 160 is located within the side wings 158 andincludes a pair of longitudinally extending side members 162, a proximalcurved end member (not shown) and a distal curved end member 164. Inother exemplary embodiments, an additional stiffener loop may beprovided. To that end, and referring to FIG. 25, the exemplary cochlearlead 106 c (which is otherwise identical to cochlear lead 106 b)includes an electrode array 108 c with a stiffener loop 142 in additionto the side wings 158 and stiffener loop 160. The stiffener loop 160 maybe formed from the same material as the stiffener loop 142 or from adifferent material. It should also be noted here that, in otherimplementations, the cochlear leads described above with reference toFIGS. 21-25 may include the distal regions described below withreference to FIGS. 26-30.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 d, is illustrated in FIGS. 26-30. The exemplarycochlear lead 106 d is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the distal region of the exemplary electrode array 108 d has apair of stiffener loops 150 and 150 a that are embedded in the flexiblebody 112. The stiffener loop 150 a, which includes a pair oflongitudinally extending side members 152 a as well as proximal anddistal curved end members 154 a and 156 a, may have the sameconfiguration as the stiffener loop 150 (as shown) or differentconfiguration. The stiffener loop 150 a is located adjacent to the tip118 and is offset slightly in the distal direction from the stiffenerloop 150. The stiffener loop 150 a, which defines a loop plane LPa, isalso located below the top ends (in the illustrated orientation) of thecontacts 114. The loop plane LPa may be parallel to the contact plane CPdefined by the ends of the contacts 114 and the loop plane LP. Inaddition to preventing buckling at or near the tip 118, the stiffenerloops 150 and 150 a control the direction that the flexible body 112bends, thereby preventing unwanted rotation of the flexible body, byvirtue of the orientation of the loop planes LP and LPa. Alternate loopplane orientations may be employed as necessary, and the stiffener loop150 may also be omitted in some implementations.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 e, is illustrated in FIGS. 31-34. The exemplarycochlear lead 106 e is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the proximal region of the exemplary electrode array 108 eincludes a stiffener loop 166 with a plurality of turns that is embeddedin the flexible body 112. The stiffener loop 166 is an open loop (i.e.,a loop with free ends) that defines a plane that may be parallel to thecontact plane, or may be in other orientations, as is described above.In the illustrated implementation, the stiffener loop is located withinthe handle tapered portion 130 and the portion of the flexible body 112adjacent to be base 120. The exemplary stiffener loop 166 includes threeturns 168-1, 168-2 and 168-3. The turns 168-1, 168-2 and 168-3 aredefined by a pair of longitudinally extending side members 170-1 to170-6, proximal curved end members 172-1, 172-2 and 172-3 and distalcurved end members 174-1 and 174-2. The exemplary stiffener loop 166also has curved free ends 176 and 178. The stiffener loop 166 may eitherbe slightly offset from, or rest on, the associated contacts 114.

The stiffness of the stiffener loop 166 is not constant along the lengthof the stiffener loop. In the illustrated implementation, the stiffnessof the stiffener loop 166 decreases from the proximal (or “basal”)region to the distal (or “apical”) region. For example, the stiffness ata location where all six of the longitudinally extending side members170-1 to 170-6 are present (i.e., at a location between the proximalcurved end member 172-3 and the curved free end 176) is greater than thestiffness at a location where fewer longitudinally extending sidemembers are present (e.g., at a location between the distal curved endmembers 174-1 and 174-2).

The exemplary stiffener loop 166 may in some instances be coextensivewith the four contacts 114 that are adjacent to the base 120, i.e., thecontacts thirteen to sixteen in the illustrated sixteen contactembodiment, in a manner similar to that illustrated in FIGS. 8 and 9.Alternatively, or in addition, a stiffener loop 166 may be locatedadjacent to the tip 118. Here, the stiffener loop 166 may in someinstances be offset from, and coextensive with, the four contacts 114that are adjacent to the tip 118, i.e., contacts one to four in theillustrated sixteen contact embodiment, in a manner similar to thatillustrated in FIGS. 13 and 14. In still other implementations, a pairof stiffener loops 166, with either the same or different dimensions asone another, may be employed adjacent to the base 120 and/or adjacent tothe tip 118 in, for example, the manners described above with referenceto FIGS. 17-20 and 26-30.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 f, is illustrated in FIGS. 35-37. The exemplarycochlear lead 106 f is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the proximal region of the exemplary electrode array 108 fincludes an undulating (or wave-shaped) stiffener loop 180 that isembedded in the flexible body 112. The stiffener loop plane (i.e., theplane that extends longitudinally through the midpoints of the waves)may be parallel to the contact plane, or may be in other orientations,as is described above. In the illustrated implementation, the stiffenerloop is located within the handle tapered portion 130 and the portion ofthe flexible body 112 adjacent to be base 120. The exemplary stiffenerloop 180 includes a pair of longitudinally extending undulating sidemembers 182, a proximal curved end member 184 and a distal curved endmember 186. The side members 182 undulate toward and away from thecontacts 114. The undulating stiffener loop 180 may either be slightlyoffset from, or rest on, the associated contacts 114.

The exemplary undulating stiffener loop 180 may in some instances becoextensive with the four contacts 114 that are adjacent to the base120, i.e., the contacts thirteen to sixteen in the illustrated sixteencontact embodiment, in a manner similar to that illustrated in FIGS. 8and 9. Alternatively, or in addition, an undulating stiffener loop 180may be located adjacent to the tip 118. Here, the stiffener loop 180 mayin some instances be offset from, and coextensive with, the fourcontacts 114 that are adjacent to the tip 118, i.e., contacts one tofour in the illustrated sixteen contact embodiment, in a manner similarto that illustrated in FIGS. 13 and 14. In still other implementations,a pair of stiffener loops 180, with either the same or differentdimensions as one another, may be employed adjacent to the base 120and/or adjacent to the tip 118 in, for example, the manners describedabove with reference to FIGS. 17-20 and 26-30.

The exemplary stiffener loop 180 is also relatively narrow and is sizedrelative to the flexible body 112 and contacts 114 in a manner similarto that illustrated in FIGS. 6, 8 and 11 in the context of stiffenerloop 142. The exemplary undulating stiffener loop 188 illustrated inFIGS. 38 and 39, which includes a pair of longitudinally extendingundulating side members 190, a proximal curved end member 192 and adistal curved end member 194, is relatively wide. The stiffener loop 188may be employed in, for example, an electrode array with a pair of sidewings similar to the electrode array described above with reference toFIGS. 21-25.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 g, is illustrated in FIGS. 40-44. The exemplarycochlear lead 106 g is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, a support 196 is attached to the above-described stiffener loop142 that is located the proximal region of the exemplary electrode array108 g. The support 196 augments the bending control aspect of theassociated portion of the electrode array 108 g, as compared to anotherwise identical electrode array without the support. The stiffenerloop 142 and support 196 define a plane that may be parallel to thecontact plane, or may be in other orientations, as is described above.In the illustrated implementation, the stiffener loop 142 and support196 are located within the handle tapered portion 130 and the portion ofthe flexible body 112 adjacent to be base 120. The exemplary support196, which includes a main body 198 and a groove 200 in which thestiffener loop 142 is located, may be a one-piece structure that iscoextensive with the entire stiffener loop 142. The groove 200 extendscompletely around the main body 198 and, accordingly, the stiffener loopside members 144 as well as proximal and distal curved end members 146and 148 are located within the groove. The support 196 may be moldedonto the stiffener loop 142. Suitable materials for the support 196include, but are not limited to, polytetrafluoroethylene (PTFE) andpolyetheretherketone (PEEK).

The stiffener loop 142 and support 196 may either be slightly offsetfrom, or rest on, the associated contacts 114. The stiffener loop 142and support 196 may in some instances be coextensive with the fourcontacts 114 that are adjacent to the base 120, i.e., the contactsthirteen to sixteen in the illustrated sixteen contact embodiment, in amanner similar to that illustrated in FIGS. 8 and 9. Alternatively, orin addition, a stiffener loop 142 and a support 196 may be locatedadjacent to the tip 118. Here, the stiffener loop 142 and support 196may in some instances be offset from, and coextensive with, the fourcontacts 114 that are adjacent to the tip 118, i.e., contacts one tofour in the illustrated sixteen contact embodiment, in a manner similarto that illustrated in FIGS. 13 and 14. In still other implementations,a pair of stiffener loops 142 (and associated supports 196), with eitherthe same or different dimensions as one another, may be employedadjacent to the base 120 and/or adjacent to the tip 118 in, for example,the manners described above with reference to FIGS. 17-20 and 26-30.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 h, is illustrated in FIGS. 45-49. The exemplarycochlear lead 106 h is substantially similar to cochlear lead 106 g andsimilar elements are represented by similar reference numerals. Here,however, a plurality of longitudinally spaced supports 202 are attachedto the above-described stiffener loop 142 that is located the proximalregion of the exemplary electrode array 108 h. The supports 202 alsoaugment the bending control aspect of the associated portion of theelectrode array 108 h, as compared to an otherwise identical electrodearray without the supports, and may be formed from the same materials(and by the same methods) as the support 196. The stiffener loop 142 andsupports 202 define a plane that may be parallel to the contact plane,or may be in other orientations, as is described above. In theillustrated implementation, the stiffener loop 142 and supports 196 arelocated within the handle tapered portion 130 and the portion of theflexible body 112 adjacent to be base 120. The exemplary supports 202each include a main body 204 and a pair of grooves 206 in which portionsof the stiffener loop side members 144 are located. The illustratedimplementation also includes an end support 208 that is associated oneof the curved end members (e.g., distal curved end member 148), whilethere is no end support associated with the other curved end member(e.g., proximal curved end member 146). The end support 208 includes amain body 210 and a U-shaped groove for the curved end member 148 of thestiffener loop 142 and adjacent portions of the side members 144. Inother implementations, there may be an end support 208 associated withboth of the stiffener loop curved end members 146 and 148, or neither ofthe stiffener loop curved end members.

The stiffener loop 142 and supports 202/208 may either be slightlyoffset from, or rest on, the associated contacts 114. The stiffener loop142 and supports 202/208 may (as a group) in some instances becoextensive with the four contacts 114 that are adjacent to the base120, i.e., the contacts thirteen to sixteen in the illustrated sixteencontact embodiment, in a manner similar to that illustrated in FIGS. 8and 9. Alternatively, or in addition, a stiffener loop 142 and supports202/208 may be located adjacent to the tip 118. Here, the stiffener loop142 and supports 202/208 may in some instances be offset from, andcoextensive with, the four contacts 114 that are adjacent to the tip118, i.e., contacts one to four in the illustrated sixteen contactembodiment, in a manner similar to that illustrated in FIGS. 13 and 14.In still other implementations, a pair of stiffener loops 166 (andassociated supports 202/208), with either the same or differentdimensions as one another, may be employed adjacent to the base 120and/or adjacent to the tip 118 in, for example, the manners describedabove with reference to FIGS. 17-20 and 26-30.

It should also be noted here that supports which are essentially thesame as, or are similar to, the supports 196, 202 and 208 may be used inconjunction with any of the other stiffener loops described herein.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 i, is illustrated in FIGS. 50-53. The exemplarycochlear lead 106 i is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the proximal region of the exemplary electrode array 108 iincludes a plurality of linked stiffener loops 214-1 to 214-4(collectively “stiffener loops 214”), each with a pair of longitudinallyextending side members 216, a proximal curved end member 218 and adistal curved end member 220. The stiffener loops 214, which areembedded in the flexible body 112, may be oriented such that the loopplanes of two of the loops (e.g., loops 214-1 and 214-3) are parallel tothe contact plane, or may be in other orientations, as is describedabove. In the illustrated implementation, the linked stiffener loops 214are located within the handle tapered portion 130 and the portion of theflexible body 112 adjacent to be base 120. The linked stiffener loops214 may either be slightly offset from, or may rest on, the associatedcontacts 114.

The linked stiffener loops 214 may in some instances be coextensive withthe four contacts 114 that are adjacent to the base 120, i.e., thecontacts thirteen to sixteen in the illustrated sixteen contactembodiment, in a manner similar to that illustrated in FIGS. 8 and 9.Alternatively, or in addition, the linked stiffener loops 214 may belocated adjacent to the tip 118. Here, the stiffener loops 214 may insome instances be offset from, and coextensive with, the four contacts114 that are adjacent to the tip 118, i.e., contacts one to four in theillustrated sixteen contact embodiment, in a manner similar to thatillustrated in FIGS. 13 and 14. In still other implementations, two setsof linked stiffener loops 214, with either the same or differentdimensions as one another, may be employed adjacent to the base 120and/or adjacent to the tip 118 in, for example, the manners describedabove with reference to FIGS. 17-20 and 26-30. The number of linkedstiffener loops may also be increased or decreased as desired.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 j, is illustrated in FIGS. 54-57. The exemplarycochlear lead 106 j is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the proximal region of the exemplary electrode array 108 jincludes an undulating stiffener loop 222 with a pair of longitudinallyextending undulating side members 224, a proximal curved end member 226and a distal curved end member 228. The side members 224 undulate towardand away from one another. The stiffener loop 222, which is embedded inthe flexible body 112, may be oriented such that the loop plane isparallel to the contact plane, or may be in other orientations, as isdescribed above. In the illustrated implementation, the stiffener loop222 is located within the handle tapered portion 130 and the portion ofthe flexible body 112 adjacent to be base 120. The stiffener loop 222may either be slightly offset from, or rest on, the associated contacts114.

The exemplary undulating stiffener loop 222 may in some instances becoextensive with the four contacts 114 that are adjacent to the base120, i.e., the contacts thirteen to sixteen in the illustrated sixteencontact embodiment, in a manner similar to that illustrated in FIGS. 8and 9. Alternatively, or in addition, a stiffener loop 222 may belocated adjacent to the tip 118. Here, the stiffener loop 222 may insome instances be offset from, and coextensive with, the four contacts114 that are adjacent to the tip 118, i.e., contacts one to four in theillustrated sixteen contact embodiment, in a manner similar to thatillustrated in FIGS. 13 and 14. In still other implementations, a pairof undulating stiffener loops 220, with either the same or differentdimensions as one another, may be employed adjacent to the base 120and/or adjacent to the tip 118 in, for example, the manners describedabove with reference to FIGS. 17-20 and 26-30.

Undulating stiffener loops similar to that illustrated in FIGS. 55-57may also be configured in such a manner that the stiffness is notconstant along the length of the stiffener loop. Referring to FIG. 57A,the stiffness of the exemplary undulating stiffener loop 222 a, whichincludes a pair of longitudinally extending undulating side members 224a, a proximal curved end member 226 a and a distal curved end member 228a, decreases from the proximal (or “basal”) region to the distal (or“apical”) region. In particular, the peak to peak distance between theundulations increases from the proximal undulation to the distalundulation in the stiffener loop 222 a, while the peak to peak distancebetween the undulations is constant in the stiffener loop 222 (FIGS.55-57).

Another exemplary cochlear lead, which is generally represented byreference numeral 106 k, is illustrated in FIGS. 58-62. The exemplarycochlear lead 106 k is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the cochlear lead includes an undulating stiffener 230 that isembedded in the flexible body 112. The stiffener plane SP (i.e., theplane that extends longitudinally through the stiffener) may be parallelto the contact plane CP (as shown), or may be in other planeorientations, as is described above. The stiffener 230 may have asinusoidal shape or other wave-like shape which cycles back and forth todefine a width between peaks 232. The undulating stiffener 230, whichalso includes proximal and distal ends 234 and 236, is located withinthe handle tapered portion 130 and the portion of the flexible body 112adjacent to be base 120. The undulating stiffener 230 may either beslightly offset from, or rest on, the associated contacts 114.

The exemplary undulating stiffener 230 may in some instances becoextensive with the seven contacts 114 that are adjacent to the base120, i.e., the contacts ten to sixteen in the illustrated sixteencontact embodiment. In other instances, a shorter undulating stiffener230 may be coextensive with the four contacts that are adjacent to thebase 120 in a manner similar to that illustrated in FIGS. 8 and 9.Alternatively, or in addition, an undulating stiffener 230 may belocated adjacent to the tip 118. Here, the undulating stiffener 230 mayin some instances be offset from, and coextensive with, the fourcontacts 114 that are adjacent to the tip 118, i.e., contacts one tofour in the illustrated sixteen contact embodiment, in a manner similarto that illustrated in FIGS. 13 and 14. In still other implementations,a pair of undulating stiffener loops 230, with either the same ordifferent dimensions as one another, may be employed adjacent to thebase 120 and/or adjacent to the tip 118 in, for example, the mannersdescribed above with reference to FIGS. 17-20 and 26-30.

The respective configurations of the proximal and distal ends 234 and236 may be adjusted as desired. Referring more specifically to FIGS. 61and 62, the proximal and distal ends 234 and 236 may simply be the pointat which the drawn filled tubing (or other material used to form theundulating stiffener 230) is terminated. The proximal and distal ends234 and 236 also point in a direction that is transverse to thelongitudinal direction to reduce the likelihood that the ends will tearthrough the electrode. Alternatively, to further reduce the likelihoodof tearing, proximal end 234′ may have a loop shape (FIG. 63), as maythe distal end (not shown).

Undulating stiffeners similar to those illustrated in FIGS. 59-63 mayalso be configured in such a manner that the stiffness is not constantalong the length of the stiffener loop. For example, the peak to peakdistance between the undulations may increase from the proximalundulation to the distal undulation so that the stiffness of theundulating stiffener decreases from proximal undulation to the distalundulation.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 l, is illustrated in FIGS. 64-66A. The exemplarycochlear lead 106 l is substantially similar to cochlear lead 106 andsimilar elements are represented by similar reference numerals. Here,however, the electrode array 108 l includes a multi-strand stiffener 238that is embedded in the flexible body 112. The multi-strand stiffener238 may be parallel to the contact plane, or may be in otherorientations, as is described above. The multi-strand stiffener 238includes a plurality of individual strands 240 (i.e., two or morestands) that are wound into a rope-like state. In those instances wherethree or more strands are employed, one of the strands may function as acore around which the other strands are wound. By way of example, themulti-strand stiffener 238 includes a core strand 240 and six otherstrands wound around the core strand. The multi-strand stiffener 238,which includes proximal and distal ends 242 and 244, is located withinthe handle tapered portion 130 and the portion of the flexible body 112adjacent to be base 120. The proximal and distal ends 242 and 244 may insome instanced be balled (as shown) by laser welding or flaming toreduce sharpness. Heat pressing (with flattened or swaged ends), tiedends, and other suitable techniques to reduce sharpness may also beemployed. The multi-strand stiffener 238 may either be slightly offsetfrom, or be in the contact plane of, the associated contacts 114.

The exemplary multi-strand stiffener 238 may in some instances becoextensive with the four contacts 114 that are adjacent to the base120, i.e., the contacts thirteen to sixteen in the illustrated sixteencontact embodiment in a manner similar to that illustrated in FIGS. 8and 9. Alternatively, or in addition, a multi-strand stiffener 238 maybe located adjacent to the tip 118. Here, the multi-strand stiffener 238may in some instances be offset from, and coextensive with, the fourcontacts 114 that are adjacent to the tip 118, i.e., contacts one tofour in the illustrated sixteen contact embodiment, in a manner similarto that illustrated in FIGS. 13 and 14. In still other implementations,a plurality of multi-strand stiffeners 238, with either the same ordifferent dimensions as one another, may be employed adjacent to thebase 120 and/or adjacent to the tip 118.

Another exemplary cochlear lead, which is generally represented byreference numeral 106 m, is illustrated in FIGS. 67-69. The exemplarycochlear lead 106 m is substantially similar to cochlear lead 106 l andsimilar elements are represented by similar reference numerals. Forexample, the electrode array 108 m includes a multi-strand stiffenerthat is embedded in the flexible body 112. Here, however, multi-strandstiffener 246 includes a plurality of individual strands 248 that arewoven into a flat braid. The multi-strand stiffener 246 may be parallelto the contact plane, or may be in other plane orientations, as isdescribed above. The multi-strand stiffener 238, which includes proximaland distal ends 250 and 252, is located within the handle taperedportion 130 and the portion of the flexible body 112 adjacent to be base120. The proximal and distal ends 250 and 252 may in some instanced beballed (as shown) by laser welding or flaming to reduce sharpness. Heatpressing (with flattened or swaged ends), tied ends, and other suitabletechniques to reduce sharpness may also be employed. The multi-strandstiffener 246 may either be slightly offset from, or may rest on, theassociated contacts 114.

The exemplary multi-strand stiffener 246 may in some instances becoextensive with the four contacts 114 that are adjacent to the base120, i.e., the contacts thirteen to sixteen in the illustrated sixteencontact embodiment in a manner similar to that illustrated in FIGS. 8and 9. Alternatively, or in addition, a multi-strand stiffener 246 maybe located adjacent to the tip 118. Here, the multi-strand stiffener 246may in some instances be offset from, and coextensive with, the fourcontacts 114 that are adjacent to the tip 118, i.e., contacts one tofour in the illustrated sixteen contact embodiment, in a manner similarto that illustrated in FIGS. 13 and 14. In still other implementations,a plurality of multi-strand stiffeners 246, with either the same ordifferent dimensions as one another, may be employed adjacent to thebase 120 and/or adjacent to the tip 118.

With respect to materials, the strands of the present multi-strandstiffeners (including strands 240 and 248 of the rope-like and flatbraid stiffeners 238 and 246 described above with reference to FIGS.64-69) may be formed from the above-described drawn filled tubing aswell as biocompatible polymer microfibers (such as polyethylene andpolypropylene microfibers), biocompatible metallic fine wire (such asplatinum, platinum-iridium, and titanium fine wire), glass fibers,carbon nanotubes or other suitable materials. With respect todimensions, the dimensions of the stiffeners (in directionsperpendicular to the longitudinal axis of the cochlear lead) may rangefrom about 0.1 mm to about 0.4 mm. For example, the diameter of arope-like braid 238 in some instances may range from about 0.1 mm toabout 0.4 mm, while in some instances the width of a flat braid 246 maybe up to about 0.4 mm and the thickness may be as small as the diameterof the strands and as large as about 0.1 mm. As used herein, the term“about” means +/−10%. The diameter of the strands themselves willdepend, at the low end, on the strand material and, at the high end, onthe intended properties (e.g., stiffness and size) of the associatedstiffener. By way of example, but not limitation, biocompatible polymermicrofibers are available in diameters as low as 0.075 mm, biocompatiblemetallic fine wires are available in diameters as low as 0.010 mm, andglass fibers are available in diameters as low as 0.005 mm.

Some multi-strand stiffeners may include strands that are identical toone another, while other multi-strand stiffeners may include one or morestands that are different in material and/or size than the otherstrands. By way of example, but not limitation, a rope-like multistrandbraid may include a biocompatible metallic fine wire core and aplurality of biocompatible polymer microfibers wound around the core, ormay include a biocompatible polymer microfiber core and a plurality ofbiocompatible metallic fine wires wound around the core. Glass fibersand other suitable materials may also be used as the core or the strandswound around the core in other implementations. The core may be the samediameter as the other strands, or may be of a difference diameter.

Although the inventions disclosed herein have been described in terms ofthe preferred embodiments above, numerous modifications and/or additionsto the above-described preferred embodiments would be readily apparentto one skilled in the art. By way of example, but not limitation, theinventions include any combination of the elements from the variousspecies and embodiments disclosed in the specification that are notalready described. For example, any two of the above-describedstiffeners may be employed in a single electrode array, with onestiffener adjacent to the base 120 and the other stiffener adjacent tothe tip 118. It is intended that the scope of the present inventionsextend to all such modifications and/or additions and that the scope ofthe present inventions is limited solely by the claims set forth below.

We claim:
 1. A cochlear implant, comprising: a housing; an antennawithin the housing; a stimulation processor within the housing operablyconnected to the antenna; and an electrode array, operably connected tothe stimulation processor, including a flexible body defining alongitudinal axis, a proximal region and a distal region, a plurality ofelectrically conductive contacts on the flexible body, and at least onemulti-strand stiffener, with the strands wound into a rope-like state,within the flexible body and electrically isolated from the electricallyconductive contacts.
 2. A cochlear implant as claimed in claim 1,wherein one of the strands of the at least one multi-strand stiffenercomprises a core strand and other strands are wound around the corestrand.
 3. A cochlear implant as claimed in claim 1, wherein the leastone multi-strand stiffener defines a diameter of about 0.1 mm to about0.4 mm.
 4. A cochlear implant as claimed in claim 1, wherein the strandsof the at least one multi-strand stiffener are selected from the groupconsisting of drawn filled tubing, biocompatible polymer microfiber,biocompatible metallic fine wire, glass fiber or carbon nanotubes.
 5. Acochlear implant as claimed in claim 1, wherein at least two of thestrands of the at least one multi-strand stiffener are formed fromdifferent materials.
 6. A cochlear implant as claimed in claim 1,wherein the electrode array includes a handle associated with theproximal region of the flexible body.
 7. A cochlear implant as claimedin claim 6, wherein the at least one multi-strand stiffener includes aportion within the handle and a portion within the proximal region ofthe flexible body; and the portions of the at least one multi-strandstiffener that are located within the handle and the proximal region ofthe flexible body are in a rope-like state.
 8. A cochlear implant asclaimed in claim 1, further comprising: a plurality of lead wires thatare respectively connected to the plurality of electrically conductivecontacts and that extend through the flexible body.
 9. A cochlearimplant as claimed in claim 1, wherein at least one multi-strandstiffener includes a proximal portion and a distal portion; the strandsare wound into a rope-like state within the proximal portion and thedistal portion.
 10. A cochlear implant as claimed in claim 1, wherein atleast one multi-strand stiffener includes a proximal end and a distalend; and at least one of the proximal and distal ends of the at leastone multi-strand stiffener is balled, flattened, swaged, or tied.
 11. Acochlear implant, comprising: a housing; an antenna within the housing;a stimulation processor within the housing operably connected to theantenna; and an electrode array, operably connected to the stimulationprocessor, including a flexible body defining a longitudinal axis, aproximal region and a distal region, a plurality of electricallyconductive contacts on the flexible body, and at least one multi-strandstiffener, with the strands woven into a flat braid, within the flexiblebody and electrically isolated from the electrically conductivecontacts.
 12. A cochlear implant as claimed in claim 11, wherein the atleast one multi-strand stiffener defines a width of up to about 0.4 mmand a thickness of no more than about 0.1 mm.
 13. A cochlear implant asclaimed in claim 11, wherein the strands of the at least onemulti-strand stiffener are selected from the group consisting of drawnfilled tubing, biocompatible polymer microfiber, biocompatible metallicfine wire, glass fiber or carbon nanotubes.
 14. A cochlear implant asclaimed in claim 11, wherein at least two of the strands of the at leastone multi-strand stiffener are formed from different materials.
 15. Acochlear implant as claimed in claim 11, wherein the electrode arrayincludes a handle associated with the proximal region of the flexiblebody.
 16. A cochlear implant as claimed in claim 15, wherein the atleast one multi-strand stiffener includes a portion within the handleand a portion within the proximal region of the flexible body.
 17. Acochlear implant as claimed in claim 11, further comprising: a pluralityof lead wires that are respectively connected to the plurality ofelectrically conductive contacts and that extend through the flexiblebody.